VERTEBRATA. 
321 
pil is round, and the tail tapering. This rule, however, 
lias many exceptions. 
2. Lacertilia , or Lizards, may be likened to Snakes.pro¬ 
vided with four limbs, each having five digits. 165 The 
bod\ T is covered with horny scales. All have teeth, which 
are simple in structure; and the halves of the lower jaw 
are firmly united in front, while those of Snakes are 
